Oil leak at Torness substation prompts beach warnings

What happened

An electrical fault at a substation within the grounds of EDF’s Torness nuclear power station, operated by SP Energy Networks, activated an automatic fire protection system. The local authority said this led to a mix of transformer oil and cooling water overflowing into the drainage system. SEPA said firewater and cooling oil were released to a site drainage system and that an unknown quantity escaped to the sea. East Lothian Council advised people not to enter the water at Thorntonloch and Skateraw beaches, to keep pets out of the water, and not to fish near the plant for at least the next 24 hours while water quality investigations continued. Clean-up teams used spill kits to block drains and collect oil. The initial oil release was reported to have been contained in a bund.

Contributing factors

The council said an electrical fault caused the automatic fire protection system to operate, and that cooling water then carried transformer oil beyond the bund into the drainage system. How much reached the sea was not reported.

Lessons learned

1. Check that substation bunds and drainage can hold firewater as well as oil under fault conditions.
2. Notify local authorities quickly if a release may reach the sea, so bathing and fishing advice can be issued while tests are pending.
3. Keep a joint clean-up plan with the site operator, the network operator and the environmental regulator for oil and cooling-water overflows.

Source

thenational.scot